1. Field
A rocker arm is disclosed for valve actuation in internal combustion engines. A rocker arm is disclosed with a reversible step-up ratio. By its use, the valve lift and the control time in internal combustion engines with suspended valves can be varied.
2. Background
The aforementioned system has the fundamental concept of making it possible to regulate the lift and the control times of the valves in an internal combustion engine. Engines with variable valve drive have major advantages over “normal” engines. They have excellent running properties over the entire rpm range. Both pollutant emissions and fuel consumption can be reduced considerably. Because the lift and the valve control times are designed to be regulatable, higher outputs can be attained even with smaller engines. The entire automotive industry is devoting major effort to this much-needed technology.
In the prior art, German Patent Disclosure DE-A 34 43 855 discloses a rocker arm system which varies the step-up ratio with the aid of a rack and a toothed quadrant. U.S. Pat. No. 4,438,736 discloses a system that includes a cam disk between the rocker arm and the valve. U.S. Pat. No. 5,937,809 discloses a system in which the control times are variable by the rotation of the rocker arm about the camshaft. U.S. Pat. No. 5,003,939 shows a system in which the camshaft rotates in an eccentric element. The valve lift is variable by rotation of the eccentric element. U.S. Pat. No. 5,857,438 shows a hydraulic valve lift regulation.